There is also ample evidence in the book that Smith is indeed severely unbalanced, if not an outright paranoid schizophrenic. During the trial, he notes of Herb Clutter, the patriarch of the family that Smith slaughtered on the same night he first met them, and whom he vaguely attempted to reassure as he tried to rob the man's house, "I wasn't kidding him. I didn't want to harm the man. I thought he was a very nice gentleman. Soft-spoken. I thought so right up to the moment I cut his throat" (Capote 244). This kind of statement shows the general mental and psychological state that Smith maintained during the crime and the trial, yet the judge would not let such evidence be presented and effectively asks for the death penalty in his final instructions to the jury, following the close of the defense's case. This case took only a day to unfold, as well, compared to the week that was taken up by the prosecution's admittedly far more substantial (due to a lack of presentable psychological evidence) case.

Possible Solutions

There is arguably little that could be done for either the rules barring the presentation of real psychological evidence during the trial or the bias that the judge showed (at least in Capote's rendering of the trial) against the defendants. The defense attorneys attempted to present mitigating psychological evidence that would at least have eliminated the death penalty from the list of applicable punishments in the all but certain case of a guilty verdict, and were prevented form doing so both by this rule and by the judge. There was admittedly very little...

Hickock spent years reading law books and writing to various groups in attempts to secure assistance for fighting appeals on their behalf, and though he was eventually somewhat successful in at least procuring some aid if not in actually avoiding the death penalty, his original attorneys should have done more to fight for their defendants than was accomplished (Capote). It is unclear whether additional character witnesses would have been permissible if testifying towards the general mental state and demeanor of the two defendants, but such testimony could have been used to lengthen the defense's case and make their point about the mitigating factor of an obvious psychological disturbance and a disconnect from the standard views of morality and acceptable human action. The defense attorneys did have their hands largely tied by the legal and interpersonal circumstances of the trial, but they did not do everything in their power to assist their defendants, either during the trial or particularly afterwards.
Conclusion

Hindsight makes it easy to judge the defense attorney's in this case; all of the battles fought fro these two defendants were ultimately losing ones, and possibly rightfully so. The essential concept of the American justice system, however, is that everyone is entitled to a fair trial, no matter how heinous their acts might be. Failing to provide this makes the whole nation guilty.